1 [C] [usu.sing] the mixture of gases that surrounds the earth or any other star, planet, etc 包围地球或其他天体的气体；大气；大气层: the earth's atmosphere 地球的大气层

2 [sing] the air in a place （某处的）空气: a smoky atmosphere 烟雾弥漫

3 [sing] the mood or feeling of a place or situation 气氛: The atmosphere of the meeting was relaxed. 会议的气氛很轻松。

4 [C] (technical术语) a measurement of pressure 大气压